About 6 months ago a contractor poured a concrete slab to serve as a porch. The slab rests directly on the ground and measures 25' by 4' and is 4" thick.
The slab has remesh under it, no gravel, but the area was poorly prepared as evidenced by the edges of the pad where dirt was piled up and it sounds hollow under one corner when you stomp on it. Additionally, the contractor didn't saw any expansion joints.
A 4' hairline crack has appeared that bisects the pad roughly in the middle.
Additionally this crack is right in the area of the entrance to the business.
I'm concerned that the crack will continue to grow as it freezes and thaws and that the pad will continue to degrade.
Should I be concerned about this crack?
Best Answer
Yep, if there wasn't insulation &/or gravel under it, that would cause hollow sounding areas. But, he definitely screwed-up on not doing a control joint...every 10' is normal as well as required for exterior slabs.
However, your best course of action is to cut that crack open. Not actually all of the way through, but at least an inch deep. Control joints are meant to crack & making them in the first place usually ensures that any cracking will happen within them.
Since you only have 1 crack though, then you really don't have any other choice but to take that crack's lead. It would be reasonable to expect that there wouldn't be any other cracks in the future after that stress relief & stress relief focusing measure.